Spitfire IIa prop pitch

[Crumpp]

The 109 had no hydraulic prop pitch, just a simple electric rpm regulator and motor.

I am confused, are you thinking what I told you was wrong? It is not. The FW-190 and the Bf-109 have the same basic system. An electric propeller controlled by a hydraulic switch. The picture I posted is the BMW 801's system which basically combines many of the separate components of the 109 system into a single unit.

The motor is operated by a hydraulic switch in normal operations and functions as a CSP. The hydraulic's reads the engine rpm and converts it hydraulic pressure with a regulator. That pressure then operates the electric motor to adjust the blade pitch to maintain the calibrated rpm. This way, both engine and propeller can be operated with a single lever in normal operations.

That is the function of the Drehzahlregular. If you look at the diagram, you can see where it is mounted to the engine pad and connects with a splined shaft. It requires an oil filter because the engines oil circulates through it and it reads the pressure to meter the amount of current to control propeller rpm, ie...blade pitch.

It seems I mixed both the 109 & 190 system.

No you haven't mixed them up. They work exactly the same. The propellers are ELECTRIC but are controlled by a hydraulic switch. I think there is confustion over the hydraulic switch. That hydraulic switch is an ELECTRICAL Switch that meters electrical energy based on hydraulic pressure. It changes the electrical current going to the propeller based on the engines oil pressure.